Thanks for your replies!
...
(How do you know T/O power was actually applied, as distinct from setting approx 40 to 45 % and checking stable as is common practice?)
...
In fact, in the sequence of events
before the occurrence of the anomalous noise and vibration on the right side of the A/C,
the only way I could
understand that T/O power had been applied right there in the bend,
is from the very sharply
pitching up noise of the turbofans (you know that noise very well, all of a sudden they seem to "scream", and as a PAX seated almost right next the source of it, it's maybe even sharper) and the consequent acceleration,
which anyone can feel with their senses, and always gives me a thrill.
This time the initial acceleration had a noticeable
transversal component; sorry to comment this with my simple words:
I felt my back side pushed backwords and sideways on the left... me, like probably all the other PAX who were looking foward to enjoy of the T/O sequence.
I have heard many other times (as a PAX in the cabin) the engines
just spooling up to a certain percent of N1 (depending on weight) for to start taxi or for verification of symmetrical thrust (and everything on green) at "taxi into position and hold" point, with or without parking brake set (I guess it is what you kindly wrote, about 40-45% N1).
I believe the take off sequence was rejected much before reaching V1, and possibly not even 80 knots, though.
Another imprecision in my initial post: the Airport elevation is just 7' (not 30'),
but this should be totally irrelevant.
Best regards,
Paolo